Fluid sensing shut-off devices with timer and methods of operation

ABSTRACT

Fluid sensing shut-off devices with timer and methods of operation to shut off fluid flow if a primary shutoff valve sticks in the on condition. An embodiment is disclosed using a microphone to sense fluid flow, with a microprocessor periodically awakening from a sleep mode to power the sensor and determine if there is flow. If there is flow, the microprocessor times flow, and if flow is not shut off within a predetermined length of time, the microprocessor shuts off the valve. The valve itself normally held in a magnetically latched, valve open state, but may be unlatched by a current pulse to close the valve. Various embodiments and applications are disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 60/672,784 filed Apr. 19, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention prevents the wasting of water in toilets.

2. Prior Art

Presently, toilet water is being wasted because of faulty flushmechanisms. This invention addresses this problem.

Known automatic fluid shut-off valves include those disclosed in U.S.Pat. No. 4,501,290 issued to Sturman et al. on Feb. 26, 1985. In FIGS.2-3 of Sturman et al., a pressure regulating electrically operableshut-off valve is shown having a permanent magnet 84 that is used tolatch a third magnetic member 98 with a magnet member 82.

Also known automatic fluid shut-off valves, in FIGS. 1-2 of U.S. Pat.No. 6,481,689 B2 issued to Grill on Nov. 19, 2002, there is shown atwo-way two-position fluid control valve having a solenoid 48. When thesolenoid 48 is electrically actuated, an armature 58 is pulled intocontact with a core 56 while a transfer tube 42, and a valve 26 coupledto the transfer tube 42, move from a first (closed) position shown inFIG. 1 to a second (opened) position shown in FIG. 2. While the fluidcontrol valve of Grill is suitable for many applications, the solenoid48 disclosed therein for both i) electromagnetically pulling thearmature 58 (and valve 26) from its closed position to its openedposition, and ii) holding the armature 58 (and valve 26) in its openedposition may be unsuitable for other applications. For example, it maybe too expensive and/or too power consuming for certain automatic fluidshut-off applications, such as those found in various places of thecommon household.

Also known in U.S. Pat. No. 6,820,856 B2 issued to Grill Nov. 24, 2004,is a two-way two-position control valve assembly operable to manuallyopen and automatically block fluid flow therethrough.

It is therefore desirable to provide a simple, energy-efficient,reliable, relatively inexpensive two-way fluid control valve assemblyfor various household and commercial applications that senses fluid flowand automatically shuts off the valve when a preset time limit hasexpired.

The present invention discloses a two-way fluid control valve with asensor that sense fluid flow and automatically shuts off the valve whena preset time limit has been reached. When fluid flow stops, the timingmechanism resets to zero.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section assembly drawing of the valve.

FIG. 2 is a full view of the assembled valve.

FIGS. 3 and 4 are circuit diagrams of the electronics used with thepreferred embodiment of the present invention.

FIG. 5 is an illustration showing the configuration and mounting of theelectronics and power supply to the valve body of the preferredembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention is its use on the water inlet ofa toilet to detect a leaking toilet valve, and shut the running wateroff after a preset time to prevent the costly and environmentally unwisewaste and loss of water.

The sensor could sense fluid by an electronic sensor, by using a probe,by sensing water level, or by detecting fluid flow audibly.

The valve could be reset manually, mechanically, electronically, orautomatically.

The fluid valve could shut off a variety of fluid flow, i.e., householdwater, gardening, irrigation, gas.

The shut-off device could be powered by virtually any source of power,i.e., AC or DC powered, solar, or powered by mechanical means.

FIG. 1 is a cross-section of the valve of one embodiment of the presentinvention taken through the inlet 20 and outlet 22 of the valve. Thevalve body 24 supports, at the left side thereof, what is referred toherein as a lower diaphragm support 26 and a spring housing 28 fastenedto the valve body 24 by screws 30. At the right side of FIG. 1, thevalve body 24 supports an actuator housing 32 held in place by screws34. Within the valve body is a shaft 36 sealed against leakage bydiaphragms 38 and 40, retained in position on the shaft by centerdiaphragm supports 42 and 44, which in turn are held in position byspring clips 46 and 48 in grooves in shaft 36.

The shaft 36 supports a seat rubber 47 within seat rubber housing 49,also held in position on the shaft by spring clips 50 and 52. O-ring 54provides a seal between the valve body 24 and the lower diaphragmsupport 26, with O-ring 56 providing a further seal along shaft 36whenever the seat rubber 46 is forced against seat 58 in the valve body.At the left end of the assembly of FIG. 1, a preloaded spring 60 pushesagainst a spring guide 62, which in turn pushes against the spring clip46 and center diaphragm support 42 to encourage shaft 36 and the variousparts coupled thereto toward the right.

At the right side of the Figure is an actuator support 64 and a cupshaped magnetic lower frame 66 with an annular magnet 68 at the rightend thereof. A magnetic plunger 70 has a slip fit in the magnet 68, withthe end of the plunger touching the right end of shaft 36. The assemblyof the lower frame 66 and magnet 68 is held in position by an upperframe 72 and the actuator housing 32. Also within the cup shaped lowerframe 66 is a bobbin 74 with a coil of wire 76 thereon.

FIG. 1 actually shows the valve in an intermediate position between itsopen position and its closed position. In particular, when plunger 70 ispushed to its left-most position against the force of spring 60, theleft face of plunger 70 will abut the adjacent face of lower frame 66 toform a substantially zero air gap magnetic circuit having a circuitportion comprised of lower frame 66 and the magnet 68 and a secondportion comprising the plunger itself. This is a substantially zero airgap magnetic circuit because the left face of plunger 70 is in contactwith the adjacent face of lower frame 66 and for the reason that theplunger 70 is a slip fit within magnet 68. Thus there is a substantialmagnetic force that will hold the plunger 70 in its left-most position,the magnetic force and the spring force of spring 60 being portioned sothat when the plunger is in its left-most position, the magnetic forcewill exceed the spring force to hold the valve in the open position.However, a current pulse through coil 76 of sufficient amplitude andduration and of appropriate sense will sufficiently reduce the magneticflux density between the left face of plunger 70 and the adjacent faceof lower frame 66 to reduce the magnetic force on plunger 70 to amagnitude less than the force of spring 60. Thus upon occurrence of sucha pulse, spring 60 will cause shaft 36 and the parts attached thereto,as well as plunger 70, to move their right-most position, forcing seatrubber 47 against seat 58 in the valve body 24 to close the valve. Whenclosed, seat rubber 46 will be firmly against seat 58 to seal againstthe seat, with O-ring 56 sealing along the shaft 36 to help preventvalve leakage. When the current pulse through coil 76 is terminated, thevalve will stay in the closed position because the air gap now existingbetween the left face of plunger 70 and the adjacent face of lower frame66 limits the flux density recovery in this area, thereby providing amagnetic valve opening force which is now less than the force of spring60 holding the valve closed. The valve may be manually reset, however,by pushing plunger 70 to the left-most position, opening the valve andagain magnetically latching the valve in the open position with the leftface of plunger 70 against the adjacent face of lower frame 66.

FIG. 2 is a view of the assembled valve without electronics. The partsviewable in that assembly are the valve body 24 with inlet and outletports 22, the actuator housing 32 held on by screws 34, plunger 70,lower diaphragm support 26 and spring housing 28 held in the assembly byscrews 30.

The electronics for controlling the fluid sensing shut-off device of thepreferred embodiments of the present invention may be seen in FIGS. 3and 4. The upper part of FIG. 3, generally indicated by the numeral 78,merely illustrates the battery power supply, in a preferred embodimentcomprising three AA batteries with various size capacitors suppressingnoise and diode D1 providing reverse voltage protection. In the lowerpart of the circuit of FIG. 3 is a microprocessor (μP) with aconventional crystal oscillator circuit 80 providing a reference clockinput for the microprocessor. The microprocessor is programmed toperiodically wake up from a sleep mode and provide sensor power on line82, which powers the circuit on FIG. 4, specifically applying sensorpower through resistor R1 to a flow sensor, in a preferred embodiment amicrophone M1, as well as to power dual operational amplifiers A1,operational amplifier A2 and comparator C1. The microphone M1 isdisposed within the body of the valve in the final assembly and maytouch the body or be slightly spaced from the body, though in eitherevent, responding to the flow noise of fluid flowing through the openvalve. Amplifiers A1 and A2 have the positive inputs thereto biased bythe voltage across resistor R2, with the positive input to comparator C1being one diode voltage drop higher than that voltage as a result of thevoltage drop across diode D2. Consequently when there is no fluid flow,and thus no microphone input, the outputs of amplifiers A1 and A2 willbe equal to the voltage on their positive inputs, namely, one diodevoltage drop below the positive input to comparator C1. Thus with noflow the output of the comparator on line 84 will be high. This holdsthe output of the precision monostable multi-vibrator MV fixed prstable, which is sensed by the microprocessor μP before reentering thesleep mode. If, however, flow has been initiated through the valvethrough the opening of another valve in series therewith, the flowsensor, microphone in the preferred embodiment, will provide an outputthat when amplified by amplifiers A1 and A2 of FIG. 4, will cause theoutput of comparator C1 to oscillate, thereby triggering themulti-vibrator MV to provide an alternating state output to themicroprocessor μP. The microprocessor, on sensing that alternatinginput, will start timing the duration of that alternating input untileither the alternating input stops or the time of flow reaches apredetermined duration, after which the microprocessor will turn onMOSFET MOS1 to apply the voltage V1, V2 across the coil of the valve ofFIG. 1. In that regard, MOSFET MOS2 is merely diode connected to absorbthe back EMF from the coil when MOSFET MOS1 is subsequently turned off.The microprocessor μP will turn on MOSFET MOS1 long enough to reduce themagnetic field and thus the magnetic force pulling plunger 70 to theleft-most position, allowing spring 60 to force the valve to theright-most or closed position, after which the current pulse may beterminated, with the valve remaining in the closed state until plunger70 is again manually pushed to the left as viewed in FIG. 1.

Also shown in FIG. 3 is a low voltage sensing capability. In particular,a voltage divider generally indicated by the numeral 86 provides twomeasures of the battery voltage VBAT to a dual ultra-low powercomparator 88 with internal reference, which will provide two outputs,one indicating a low battery (the word battery as used herein an in theclaims including multiple batteries) and the other output indicating thebattery is so low as to risk malfunction of the sensing system if thevalve is not immediately closed. Thus on first sensing the low battery,the microprocessor will provide an output to cause a low frequencyflashing of light-emitting diode LED1, with a still lower batteryvoltage indication causing the microprocessor to pulse MOSFET MOS1 on toclose the valve.

Now referring to FIG. 5, the manner in which the electronics and batterypower supply attach to the valve body 24 may be seen. In particular,case 90 houses a printed circuit board with the microprocessor μP andother electronics therein, with cover 92 covering the three AA batteriesfor the battery power supply. The microphone in the preferred embodimentis mounted on the printed circuit board itself and extends into thevalve body 24 for picking up the sound and vibrations from the turbulentfluid flow through the valve.

The preferred embodiment of the present invention is intended for use inthe water supply line for a toilet to shut off the water flow in theevent the normal toilet water flow shut-off valve malfunctions for anyreason. However, the present invention may be used in other instances topreserve water or protect property in systems wherein normal water floweither occurs for a predetermined time period, or at least for apredetermined maximum time period. For instance, one such other use maybe in the water supply line to an ice cube maker in a refrigerator. Inthis application, if the solenoid valve supplying water to the ice cubemaker locks in the valve open condition, substantial property damage canresult unless an automatic backup shut-off valve is used, such as thepresent invention valve. Other applications could include dishwashersand clothes washers, irrigation systems, and the like, wherein muchwater can be wasted and substantial damage property can result from avalve stuck in the on position. In that regard, valve systems inaccordance with the present invention may readily be scaled toaccommodate large or small flows as required. By having themicroprocessor in the sleep mode a large majority of the time, batterylife in the system of the present invention may approach the shelf lifeof the batteries. Obviously the valve systems of the present inventioncould be powered from 110V AC power, though battery power is preferredto minimize installation difficulty and cost. Also while a microphoneand microprocessor based system has been disclosed herein, obviouslyother types of flow sensors and control electronics may be used asdesired. In that regard, the flow duration before automatic shut-offcould be varied for different applications, and if desirable, could bemade field programmable. Thus while certain preferred embodiments of thepresent invention have been disclosed and described herein for purposesof illustration and not for purposes of limitation, it will beunderstood by those skilled in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the invention.

1. A fluid sensing shut-off device comprising: a valve having a valveopen position allowing fluid flow between a valve inlet and a valveoutlet, and a valve closed position preventing flow between the valveinlet and the valve outlet; the valve being encouraged to the valveclosed position by a spring force; a stationary magnetic circuitportion; a magnetic member moveable within the magnetic circuit betweenfirst and second positions, the magnetic member forming a closedmagnetic circuit having a substantially zero air gap and disposed tohold the valve in the valve open position when in the first position;one of the stationary magnetic circuit portion and the magnetic memberincluding a permanent magnet, the permanent magnet magnetically holdingthe magnetic member in the first position with a magnetic forceexceeding the spring force once moved to the first position; a coildisposed to temporarily decrease the magnetic force to less than thespring force on receipt of a current pulse in the coil to allow thespring force to move the magnetic member to its second position and toallow the spring force to move the valve to the closed position; asensor configured to sense fluid flow through the valve, independent ofthe destination of that fluid; a timer coupled to the sensor to sensethe length of time of fluid flow; and, circuitry coupled to the timer toprovide a current pulse to the coil if a duration of fluid flow exceedsa predetermined time limit to allow the spring force to move the valveto the valve closed position; the fluid sensing shut-off device beingmanually operable to return the magnetic member to its first positionand the valve to the open position to be magnetically retained at therespective positions without providing a current pulse or otherelectrical power to the coil.
 2. The device of claim 1 wherein thepermanent magnet is included in the stationary magnetic circuit portion.3. The device of claim 1 wherein the sensor comprises a microphonedisposed to sense fluid flow through the valve.
 4. The device of claim 1wherein the sensor, the timer and the circuitry coupled to the timer toprovide a current pulse to the coil are battery powered.
 5. The deviceof claim 4 wherein the sensor is periodically powered to sense fluidflow.
 6. The device of claim 5 wherein the sensor and timer areconfigured to remain powered when flow is sensed until flow stops or thecircuitry coupled to the timer provides a pulse to the coil to move thevalve to the valve closed position.
 7. The device of claim 4 furthercomprising a battery voltage sensor for sensing and indicating a lowbattery voltage.
 8. The device of claim 7 further comprising circuitryfor pulsing the coil to move the valve to the valve closed positionbefore the battery discharges to a level inadequate to pulse the coil tomove the valve to the valve closed position.
 9. The device of claim 1further comprising a microprocessor.
 10. The device of claim 9 whereinthe timer is a microprocessor operating under program control.
 11. Thedevice of claim 10 wherein the microprocessor is programmed to spendmost it its time in a sleep mode, and to periodically wake up and powerthe sensor to determine if fluid is flowing through the valve.
 12. Thedevice of claim 11 wherein the microprocessor is programmed to continuepowering the sensor once fluid flow is sensed at least until eitherfluid flow stops or the duration of fluid flow exceeds the predeterminedtime limit and the coil is pulsed.
 13. The device of claim 12 furthercomprising a battery voltage sensor for sensing and indicating a lowbattery voltage, the microprocessor being coupled to the output of lowbattery voltage sensor and programmed to flash a visible warning when alow battery voltage is sensed.
 14. The device of claim 13 wherein themicroprocessor is also programmed to cause a current pulse to the coilto move the valve to the closed position before the battery becomes toodischarged.
 15. A water sensing shut-off device comprising: a valvehaving a valve open position allowing water flow between a valve inletand a valve outlet, and a valve closed position preventing flow betweenthe valve inlet and the valve outlet; the valve being encouraged to thevalve closed position by a spring force; a stationary magnetic circuitportion; a magnetic member moveable within the magnetic circuit betweenfirst and second positions, the magnetic member forming a closedmagnetic circuit having a substantially zero air gap and disposed tohold the valve in the valve open position when in the first position;one of the stationary magnetic circuit portion and the magnetic memberincluding a permanent magnet, the permanent magnet magnetically holdingthe magnetic member in the first position with a magnetic forceexceeding the spring force once moved to the first position; a coildisposed to temporarily decrease the magnetic force to less than thespring force on receipt of a current pulse in the coil to allow thespring force to move the magnetic member to its second position and toallow the spring force to move the valve to the closed position; asensor configured to sense water flow though the valve, independent ofthe destination of the water flow; a timer coupled to the sensor tosense the length of time of water flow; and, circuitry coupled to thetimer to provide a current pulse to the coil if a duration of water flowexceeds a predetermined time limit to allow the spring force to move thevalve to the valve closed position; the water sensing shut-off devicebeing manually operable to return the magnetic member to its firstposition and the valve to the open position to be magnetically retainedat the respective positions without providing a current pulse to thecoil.
 16. The device of claim 15 wherein the permanent magnet isincluded in the stationary magnetic circuit portion.
 17. The device ofclaim 15 wherein the sensor comprises a microphone disposed to sensewater flow through the valve.
 18. The device of claim 15 wherein thesensor, the timer and the circuitry coupled to the timer to provide acurrent pulse to the coil are battery powered.
 19. The device of claim18 wherein the sensor is periodically powered to sense water flow. 20.The device of claim 19 wherein the sensor and timer are configured toremain powered when flow is sensed until flow stops or the circuitrycoupled to the timer provides a pulse to the coil to move the valve tothe valve closed position.
 21. The device of claim 18 further comprisinga battery voltage sensor for sensing and indicating a low batteryvoltage.
 22. The device of claim 21 further comprising circuitry forpulsing the coil to move the valve to the valve closed position beforethe battery discharges to a level inadequate to pulse the coil to movethe valve to the valve closed position.
 23. The device of claim 15further comprising a microprocessor.
 24. The device of claim 23 whereinthe timer is a microprocessor operating under program control.
 25. Thedevice of claim 24 wherein the microprocessor is programmed to spendmost it its time in a sleep mode, and to periodically wake up and powerthe sensor to determine if water is flowing through the valve.
 26. Thedevice of claim 25 wherein the microprocessor is programmed to continuepowering the sensor once water flow is sensed at least until eitherwater flow stops or the duration of water flow exceeds the predeterminedtime limit and the coil is pulsed.
 27. The device of claim 26 furthercomprising a battery voltage sensor for sensing and indicating a lowbattery voltage, the microprocessor being coupled to the output of lowbattery voltage sensor and programmed to flash a visible warning when alow battery voltage is sensed.
 28. The device of claim 27 wherein themicroprocessor is also programmed to cause a current pulse to the coilto move the valve to the closed position before the battery becomes toodischarged.